New Outlook for Windows cannot add two IMAP accounts

Remove each mailbox from all devices in New Outlook—not merely from the current PC—then add it through IMAP with MXroute’s exact settings; this is the supported action that clears the Microsoft Cloud copy of a non-Microsoft account configuration.^1^

Clear the retained account configuration

Repeat these steps for each mailbox:

1. In New Outlook, open View → View settings → Accounts → Your accounts.
   Alternatively, use File → Account info → Accounts → Your accounts.
2. Locate the mailbox and select Manage → Remove.
3. In Remove Account, choose Remove from all devices, not Remove from this device.
4. Close New Outlook completely and reopen it.

Caution: “Remove from all devices” removes that account and its Microsoft Cloud data from Outlook clients. Items existing only in Microsoft Cloud—not in MXroute webmail—could be permanently lost. Check calendars or other cloud-only content before proceeding.^1^

This differs from deleting Windows credentials: New Outlook’s non-Microsoft account synchronization can retain account state in Microsoft Cloud. A closely matching New Outlook case reports that removal from all devices clears this server-side cache.^2^

Add each mailbox again

1. Open Settings → Accounts → Your accounts → Add account.
2. Enter the complete mailbox address and select Continue.
3. Choose IMAP or Advanced setup, then expose the manual fields.
4. If shown, disable Use recommended settings.
5. Enter the exact MXroute values for:
   • IMAP hostname, port, and encryption
   • SMTP hostname, port, and encryption
   • Full mailbox address as the username
   • Mailbox password
6. Accept the Sync your IMAP account to Outlook prompt. New Outlook uses cloud synchronization for non-Microsoft IMAP accounts.
7. Add the second mailbox the same way.

New Outlook supports multiple “other” accounts connected through IMAP or POP, so two IMAP accounts are not inherently unsupported.^3^

Since both mailboxes already work in Classic Outlook and Outlook for Mac, repeating password or basic server-connectivity checks is unlikely to distinguish this failure. The reported INVALIDCREDENTIALS INTERACTIONREQUIRED does not by itself prove that the mailbox password is wrong.

Determine which hostname New Outlook is actually using

New Outlook does not have a documented user-facing connection-status dialog equivalent to Classic Outlook that reliably exposes the effective cloud-side IMAP endpoint. Use these two checks instead:

1. Ask MXroute to inspect its IMAP/SMTP connection logs during a timestamped add-account attempt.
   • A connection to the former Verpex hostname confirms stale endpoint selection.
   • No connection reaching MXroute indicates failure before authentication reaches the new provider.
2. In New Outlook, select Help → Get Diagnostics → Upload Logs or Send Diagnostics. Submit the attempt immediately after reproducing it. Microsoft documents this route for collecting diagnostic information for a support investigation.^4^

If the account is missing or still uses the old host

If a mailbox does not appear under Your accounts, or Remove from all devices followed by manual setup still restores the Verpex hostname, local Credential Manager cleanup is unlikely to clear the remaining record. A matching provider-migration case indicates that public forum contributors cannot clear an orphaned Microsoft Cloud account configuration; Microsoft Support must investigate it.^5^

Open Help → Support in New Outlook and provide:

• Both affected mailbox addresses, redacted in screenshots if posted publicly
• Migration date and old/new provider names
• Old and new IMAP/SMTP hostnames
• Exact failure time and time zone
• INVALIDCREDENTIALS INTERACTIONREQUIRED
• Confirmation that Classic Outlook and Outlook for Mac work
• Confirmation that Remove from all devices was performed
• Whether MXroute saw any connection attempt
• The uploaded diagnostic-log reference

Until the cloud-held configuration is cleared or corrected, continue using Classic Outlook; Microsoft supports running Classic and New Outlook side by side.^6^

References

1. [New Outlook](https://support.microsoft.com/outlook/getstarted/add-an-email-account-to-outlook-for-windows#remove-an-account-in-new-outlook)
2. Outlook new has stopped receiving sending AOL email in app? - Microsoft Q&A
3. Supported accounts in new Outlook for Windows
4. Contact support and provide feedback in new Outlook for Windows | Microsoft Support
5. IMAP email provider changes the backend - Microsoft Q&A
6. Deployment overview for the new Outlook for Windows